1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus, such as circuit breakers. The disclosed concept also relates to close latch interlock assemblies for circuit breakers.
2. Background Information
Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as, for example, current overloads, short circuits, abnormal voltage and other fault conditions. Typically, circuit breakers include an operating mechanism, which opens electrical contact assemblies to interrupt the flow of current through the conductors of an electrical system in response to such fault conditions as detected, for example, by a trip unit. The electrical contact assemblies include stationary electrical contacts and corresponding movable electrical contacts that are separable from the stationary electrical contacts.
Among other components, the operating mechanisms of some stored energy circuit breakers, for example, typically include a pole shaft, a trip actuator assembly, a closing assembly and an opening assembly. The trip actuator assembly responds to the trip unit and actuates the operating mechanism. The closing assembly and the opening assembly may have some common elements, which are structured to move the movable electrical contacts between a first, open position, wherein the movable and stationary electrical contacts are separated, and a second, closed position, wherein the movable and stationary electrical contacts are electrically connected. Specifically, the movable electrical contacts are coupled to the pole shaft. Elements of both the closing assembly and the opening assembly, which are also pivotably coupled to the pole shaft, pivot the pole shaft in order to effectuate the closing and opening of the electrical contacts. The closing assembly includes a chargeable stored energy mechanism such as, for example and without limitation, a closing spring, and a close button to actuate (e.g., discharge) the closing spring to facilitate the closing process.
As shown, for example, in FIGS. 1 and 2, such circuit breakers (see circuit breaker 2 partially shown in FIG. 1) typically include an interlock assembly 4 for preventing the closing spring 6 (partially shown in phantom line drawing in FIG. 1) from undesirably or unintentionally discharging. For example and without limitation, such unintended discharges can occur if the operator keeps the close button 8 of the circuit breaker 2 depressed (partially shown in phantom line drawing in FIG. 1), and the circuit breaker 2 is equipped with a motor operator (not shown). It can also result from shock and/or vibration, which causes unintended movement of circuit breaker components (e.g., without limitation, close D-shaft 12).
The interlock assembly 4 includes an elongated linking element, commonly referred to as the close block link 10, which cooperates with the close D-shaft 12 of the circuit breaker 2. More specifically, a first end 14 of the close block link 10 is coupled to a lever 18 of the close D-shaft 12, and a second end 16 extends outwardly away from the close D-shaft 12, as shown. A portion of the second end 16 cooperates with a spring release member 20, as partially shown in phantom line drawing in FIG. 1, when the close button 8 of the circuit breaker 2 is actuated (e.g., depressed downward from the perspective of FIG. 1, as partially shown in phantom line drawing), to release (e.g., discharge) the closing spring 6. Otherwise, when the circuit breaker 2 is not ready to close (e.g., when the closing spring 6 is discharged), the interlock assembly 4 forms an interlock to resist undesired repetitive or unintentional discharging of the closing spring 6.
There is, therefore, room for improvement in electrical switching apparatus, such as circuit breakers, and in close latch interlock assemblies therefor.